Ceiling illuminating system



Aug. 4, 1964 HSKRUGER Re. 25,628

CEILING ILLUMINATING SYSTEM Original Filed June 2'7, 1960 3 Sheets-Sheet1 Aug. 4,1964 M. H. KRUGER CEILING ILLUMINATING sys'rm Original FiledJune 27, i960 3 Sheets-Sheet 2 4, 1954 M. H. KRUGER Re. 25,628

CEILING ILLUMINATING Original Filed June 27, 1960 I 5 Sheets-Sheet 3 L Jl [.J 19L] w? w 52 7/! Y 2 I I L z a u T J [N] 1 I United States Patent25,628 CEILING ILLUMINATING SYSTEM Michael Henry Kruger, Chestnut Hill,Mass., assignor to Smithcraft Corporation, Chelsea, Mass, a corporationof Massachusetts Original No. 3,094,285, dated June 18, 1963, Ser. No.

39,058, June 27, 1960. Application for reissue Dec. 19,

1963, Ser. No. 342,582

23 Claims. (Cl. 2409) Matter enclosed in heavy brackets appears in theoriginal patent but forms no part of this reissue specification; matterprinted in italics indicates the additions made by reissue.

The invention relates to lighting at ceilings and more particularly tolighting assemblies adapted to be mounted below overhead structure inrooms.

The apparent, visible ceilings of present-day rooms have been disposedconsiderably below the structural overhead when providing for airconditioning (including cooling and heating), and air ducts, and otherservices such as electrical power, telephone wiring and sprinklingsystems are placed in the cavity thus defined, above the apparentceiling and lighting means associated therewith.

Similarly, when it is desired to avoid having pendant light fixtureshanging down from the visible ceiling, while employing relativelyinexpensive acoustical sheet for sound damping, the common practice hasbeen to suspend the acoustical sheet across the room to define a planarceiling, well below the structural overhead, and lighting fixtures havebeen recessed into the cavity.

While the dirt catching and unsightly pendant fixtures are thuseliminated, such has been achieved with a ceiling comprised ofalternating, brilliantly-lighted zones, where the recessed lightsappear, and dark zones, comprised of opaque, acoustical sheet. Thiscreates risk of eyestrain to room occupants. Such ceilings have beenconsidered to be so unattractive and otherwise unsuitable that luminousceilings have been frequently employed, which are more expensive, andhave often required more cavity space.

To provide a building with a given apparent ceiling height, buildingcosts obviously greatly increase with increase of the depth of the deadcavity, and these costs are especially great where air conditioning isprovided and where relatively more expensive ceiling arrangements areemployed rather than opaque, acoustical sheet. Many existing buildingswith low structural ceilings cannot practically be modernized along thelines suggested above.

A principal objective of the invention is, therefore, the provision ofceiling assemblies which overcome the abovementioned disadvantages ofthe prior art. More particularly the invention has as one objective thedecrease in needed cavity space in a well-illuminated, air conditionedroom. Another objective is the better utilization of acoustical sheetmaterial, so that it forms an attractive and functional secondary sourceof illumination, and the overall ceiling is devoid of eyestraining largecontrasting brightness regions. Another objective is increase inapparent ceiling height in a room having an acoustical sheet ceiling andno pendant light fixtures.

Other objectives include providing a grid assembly of a strong and rigidconstruction having a number of integrated functions to achieveinexpensive, small cavity, combinations of even illumination, airconditioning, ready partitioning and acoustical damping; and a gridcoupling means permitting rapid, economical, rigid and accurate on-siteassembling.

These and other objects and features of the invention will be more fullyappreciated with consideration of the following detailed description anddrawings.

In the drawings:

FIG. 1 is a partially cutaway perspective looking down upon a portion ofone embodiment of the ceiling according to the invention;

FIG. 2 is a partially exploded view of a portion of the ceiling of FIG.1 illustrating the relationship of light and corresponding light shield;

FIG. 3 is a section of the ceiling of FIG. 1 taken on lines 3-3;

FIG. 3a is a view similar to FIG. 3 of another preferred embodiment;

FIG. 4 is a partially exploded view on an enlarged scale of theinterconnection of a juncture of grid members in the ceiling of FIG. 1;

FIG. 5 is a section of a juncture of 4 grid members as occurs in centralportions of the ceiling;

FIG. 6 is a view similar to FIG. 5 of the juncture of 3 grid members asoccurs at the sides of the ceiling;

FIG. 7 is a view similar to FIGS. 5 and 6 illustrating a corner of thegrid assembly;

FIG. 8 is illustrative of a novel grid member adapted to serve asacoustical sheet support, as a light reflector and cutoff and as an airregister;

FIG. 9 is a view from below of a variation of the system of FIG. 1wherein grid members parallel with the tubular light are of substantialvolume similar to the grid members of FIG. 8, and in which successivegrid members are in end-to-end communication serving as ducts fortransmission of air as well as providing air registers;

FIG. 10 is a partially cutaway view from below of the integratedilluminated ceiling of FIG. 1.

The present-day common low-cost acoustical sheet ceilings noted abovehave been comprised of a suspended metal frame upon which acousticalsheet has rested generally fiush with the lower surfaces of theframework. At spaced intervals fluorescent light fixtures have beenrecessed with lamp holders, lamps, and wiring well above the plane ofthe apparent acoustical ceiling. Such ceilings are dark, with brightareas only where the recessed lights occur. This results in eyestraindue to the variations in the ceiling brightness level. There is anineflicient use of light and poor appearance. In accordance with theteachings of the invention herein utilizing generally the same kinds andquantities of materials, there is provided a ceiling having a generallyuniform brightness level illuminating the room below. There is achieveda ceiling, which, from a standpoint of illumination is competitivelysimilar to the relatively very expensive lighting systems known asluminous ceilings. Moreover, a substantial increase in apparent ceilingheight is achieved.

Referring to the preferred embodiment of FIG. 1, grid 20 is formed by amultiplicity of parallel, elongated grid members 24 suspended by wires26 from overhead struc ture, connected with similar cross-grid members22.

Each grid member is provided with horizontal upper ledges 28 and ledges29 which may be divided in the center by upstanding longitudinal ribs 30having spaced-part holes through which the supporting wires are secured,or may be smooth as suggested by the form of cross-grid member ledges29, and supported by wires, vertical pipes or other such means engagingthe grid members at the ledges or otherwise. Sheets 32 of acousticalmaterial, e. g. sound-absorbent fiber, which may be acoustical board,rolled batting or other sheet means are horizontally disposed, supportedat least in part by the ledges. Where employed, ribs 30 promotepositioning of the sheets during assembling.

A plurality of fluorescent light tube means 34 are supported betweenpairs of grid members 24, parallel therewith below ledges 28 and 29 andsheets 32. In the chicient use of materials of the embodiment of FIG. 1,crossgrid members 22, positioning grid members 24 also support ends ofthe light tube means.

Each light tube means is comprised of at least one tubular fluorescentbulb 36 and appropriate electrical connections, e.g. opposed lampholders and a formed metal strip 38, carrying ballast and wiring. Inthis preferred embodiment the metal strip provides ledges 31 which maybe similar to ledges 28, 29 for support of sheet 32. An elongatedclosure 39 overlies and closes the strip 38.

A light-shielding member 40 comprised preferably of optically treatedplastic is disposed below each bulb 36 and is likewise preferablysupported by opposed cross grid members 22. The light-shielding members40 extend longitudinally with the bulbs and have a substantiallytransverse dimension, relative to the bulb, with each longitudinalextremity 41 thereof disposed substantially to the side from thecorresponding side of the bulb. The longitudinal extremities 41 can becomprised of integral, upturned portions, with overlying margins adaptedto rest upon supporting pins 42 held by cross grid members 22, see FIG.2. The light-shielding member has a refracting characteristic, thehorizontal surface directs incident light steeply downward, and theupturned sides direct light toward the grid members 24.

The grid members 24 are provided with downward extending, longitudinalsurfaces 25 parallel with the fluorescent tubes 36.

Referring to FIG. 3, the lower longitudinal edges of grid memberdownward-extending surfaces 25, the longitudinal edges oflight-diffusing shields 40 and the bulbs 36 are aligned as indicated sothat rays from the bulb passing laterally, clear of the light-shieldingmember impinge either upon grid member surfaces 25 or the undersurfaceof sheets 32, hence no bare bulb is exposed to view from below. The gridmember surfaces 25 and the undersurface of the acoustical sheets 32 areprovided with a light-reflecting finish, and, being thus illuminated bythe light tube means, provide secondary illumination to the room, in aceiling of generally even brightness. The shielding member may transmitdirect relatively high level illumination, but in rays at such steepangles that they are not observable in looking at the ceiling withnormal angles of view.

Both grid members 24 and the cross-grid members in this preferredembodiment are box-formed sheet metal channels defining longitudinalpassages through which wiring can be easily run, and providedouble-walled sound barriers.

The hollow box cross section of the grid members makes the grid membersrigid, self-supporting, and uniquely adapted to be interengaged withcouplers to provide a strong, rigid and accurately aligned ceiling grid,as hereafter discussed with reference to FIGS. 4-7.

Referring to FIG. 3a, grid members 24 have downwardly extending, opposedsurfaces 25' flaring outwardly from narrow undersurface 27, either flator rounded, the only portion not exposed to direct light. Indeed, insome instances this could be a V point in cross section, eliminatingeven this thin line of shadow, but the thin shadow line gives adesirable texture to the ceiling, permits substantial volume to beenclosed by the grid member, important for instance for passage of airas hereafter described, and does not cause eyestrain.

The light means here comprises a pair of light tubes 36' and thelight-shielding member 40' comprises a planar-diffusing member comprisedof vertically arranged, intersecting strips 47. It will be noted thatthis lightshielding member is open permitting air to pass there throughand the above acoustical sheet is thus advantageously exposed to soundfor damping. Each grid member along a bulb serves as a light cutoff.Lower horizontal edge 29 of each of such grid members is on a line ofsight with the lateral extremity of the light-shielding member 40',intersecting the horizontal at an angle A. A line of sight between thatlight-shielding member extremity and the upper limb 37 of the adjacentlight means intersects the horizontal at smaller angle B, henceeyestraining bare bulb is not visible from below, between thecorresponding edges of the shielding member and the grid member. Where,however, the comfort requirements of a room require that only lightradiated at slight angles to the horizontal be cut OH, or whererelatively close spacing of parallel grid members 24 or 24 can beemployed, e.g. to house building services as hereafter discussed, thegrid members 24 are employed alone, without light-shielding members, andserve as light cutoffs as suggested by the cutaway of FIG. 3a. Indeed,cross-grid members 22 similarly serve to promote comfort by lightcutoff, and the grid alone will block all direct light radiating towardsremote points on the floor below, and hence is particularly advantageousin very large, low ceilinged rooms.

The undersurface of the right hand grid member in this figure isprovided with an elongated, downwardly extending rib 35 engaged with amatching groove in the head of wall partition 45, positioning andsecuring it.

Referring to FIGS. 4-7, central coupler 46, side coupler 48 and cornercoupler 50 each is provided with plug portions 52 adapted to engageinternally end-connected grid members 24 and also cross-grid members 22,see FIG. 4. These plug portions have perimeter dimensions substantiallythe same as the internal dimensions of the grid members. Plugs on eitherside of one plug provide abutment shoulder means adapted to be abuttedby grid member and engaging that plug. Each plug has a substantialoutward extent in contact with corresponding inner surface portions ofits grid member. Thus a fivesided snug fit between a grid member end andits coupler is achieved. They are locked together by means of tabs 58struck from portions of the grid member, preferably ledge 28, overlyinga hollow horizontal end of the coupler. During assembling these tabs arebent into the hollow of the coupler and interior edge 60 of each of thetabs engages the inner surface 57 of the plug end, locking coupler andgrid member from relative movement. Thus adjacent grid members arerigidly and rapidly locked together during on-site assembling.

Holes are provided in plug ends providing, when desired, communicationbetween grid members at the connections. While shown to be oval,adequate for low air flow, where higher flows are involved the holes areshaped to minimize air flow resistance and sound. An insert 59 (see FIG.10) is inserted in the bottom hollow end of each coupler to enhanceappearance, and for air sealing. It will be appreciated that since alarge number of grid members are advantageously employed in a room, theair flow through each can be small, hence pressure drop and noise willbe minimized, and dirt discoloration at the outlets avoided. The uniquecouplers are adapted to turn the air from grid members 24 to cross-gridmembers 22, hence air distribution can be in any desired pattern, andcan be changed as needed when the room partitioning is rearranged. Thusthere are important functions the grid members perform in addition tothe serving as light cutoff and together with the sheet 32, serving assource of secondary illumination. As in FIG. 8 a grid member 60 isprovided with perforated sides and an air duct is connected from above,and the grid member serves as an air register. The upper portions ofthese grid members are quite wide providing a substantial air capacity.The downward extending sides 72 converge inwardly to a relatively narrowundersurface 74. As these sloped sides are exposed to illumination, darkceiling portions are limited to the narrow ceiling texturingundersurfaces while a large grid member volume is achieved.

Referring to FIG. 9 grid members have substantially the same crosssection, but here serve as air ducts as well as being provided with airregister means including air register grilles 82 and opening 83 in thegrid sides, transmitting air across the room to outlets. Couplerssimilar to those described above are employed, air passage holes beingprovided in the coupler plug-end walls inserted in duct grid members.

Referring to FIG. 10, it will be appreciated that the ceiling of theinvention achieves an apparent ceiling height which is virtually theuppermost extent of the assembly itself. Thus it is possible to avoidwaste cavity space, and to lower the structural overhead in newconstruction, achieving substantial savings in building materials. Forthe first time it is now practical to modernize old low ceilingbuildings in a relatively inexpensive manner. From the view of FIG. 10,it will also be appreciated that room partitions of a thickness equal tothe grid members 22, 24 can be set in place throughout the room,reaching to the ceiling with no changes in the ceiling lighting beingnecessary. Such partitions are anchored at the top to grid membersadapted to the purpose, see FIG. 3a. It will also be appreciated thatthe bulbs are exposed for maintenance, the light-shield members 40 beingremoved by simply sliding them to one side while pushing slightlyupwards (see FIG. 3).

Finally, it will be appreciated that each of these grid members cancarry building services. Within a grid member a sprinking system can beinstalled therethrough. An intercommunication speaker system adapted toplay music, complete with wiring can be installed. Special highintensity spotlights can be installed and wired. And very importantly, alow flow, even air distribution system is provided, which uniquely canbe changed to adequately ventilate cubbyholes partitioned off, wheneverdesired, and all of this is achieved with a ceiling that can in fact bethe structural overhead, to which can be applied a sheet of sounddamping material.

It will be understood that the foregoing are descriptions and drawingsof preferred embodiments and various details thereof can be modifiedwithin the spirit and scope of the invention.

I claim:

1. An illuminating, sound-absorbent ceiling comprising a multiplicity ofelongated grid members adapted to be suspended horizontally fromoverhead structure, each grid member being provided with an elongatedupper surface, acoustical sheet means having a light reflective lowersurface disposed over and supported at least in part by said grid memberupper surfaces, at least some of said grid members being spaced apartfrom and parallel with adjacent grid members forming a plurality of gridmember pairs, a plurality of elongated light tube means, meanssupporting each light tube means between a said pair of grid members andparallel therewith below said lower surface of said acoustical sheetmeans, each grid member disposed along the side of a light tube meanshaving a generally continuous surface parallel with the correspondinglight tube means and extending downwardly to a lower horizontal edgebelow said light tube means, a plurality of light-shielding means, onedisposed below, along the length of each light tube means, eachlightshielding means being substantially narrower than the space betweenthe grid members of the corresponding pair but wider than thecorresponding light tube means, having each longitudinal upper edgespaced aside from the corresponding side of said light tube means, eachlight tube means, its light-shielding means, and the corresponding pairof grid members being relatively positioned so that a line of sightthrough each light-shielding means longitudinal upper edge and the lowerinner edge of the corresponding grid member intersects the horizontal atan angle no less than that of a line of sight between that shieldingmeans edge and the upper limb of the corresponding light tube means.

2. The ceiling of claim 1 wherein at least some of said gird membersdefine hollow longitudinal chambers, each provided with an air inletmeans and an air outlet means, thereby serving as a portion of the airservice system.

3. The ceiling of claim 2 wherein the air inlet means of some of saidhollow grid members comprise other of said hollow grid members in directend communication therewith.

4. The ceiling of claim 2 wherein the outlet means of at least one ofsaid gird members is an air register means provided in a longitudinalwall of said grid member.

5. The ceiling of claim 1 wherein a plurality of said light tube meansare disposed in a parallel relationship across said ceiling, spacedalternately with parallel grid members, those gird members positionedbetween light tube means being shared grid members providing twogenerally oppositely directed, downwardly extending surfaces, onedisposed toward each of said light tube means.

6. The ceiling of claim 5 wherein at least some of said shared gridmembers have two spaced-apart walls providing said two downwardlyextending surfaces, said grid members further being provided withadditional longitudinal, enclosing wall portions, therebydefining'hollow grid member enclosures adapted to serve as a housing forbuilding services.

7. The ceiling of claim 1 wherein said light-shielding means comprisesan optically treated plastic member having a horizontal surface portionadapted to refract light steeply downwards, and having upstanding sideportions comprising the lateral extremities adapted to refract lighttowards corresponding grid member downwardly-extending surfaces.

8. The ceiling of claim 1 wherein undersurfaces of at least some of saidgrid members are each provided with a longitudinal engagement means,adapted to engage with the upper edge portions of room partitions forpositioning and support thereof without disrupting the light andappearance of the ceiling.

9. For use as an illuminating, sound-absorbent ceiling, a pair ofparallel, spaced-apart, elongated grid members adapted to be disposed ina horizontal plane, each grid member having a longitudinal surfaceextending downwardly to a horizontal lower longitudinal edge, agenerally planar sound-absorbent means disposed horizontally at a levelabove said grid member surfaces and positioned between them, the lowersurface of said soundabsorbent means being light-reflective, anelongated light tube means mounted parallel with and between said gridmembers, below said sound-absorbent means and above said lowerlongitudinal edges of said grid members, and an elongated lightshielding means disposed under said light tube means, said shieldingmeans being adapted to prevent the transmission of glaring direct lightinto the eyes of persons below said ceiling, said shielding means beingwider than said light tube means but narrower than the space betweensaid grid members leaving portions of said light-reflective surface ofsaid sound-absorbent means unshielded, the longitudinal edges of saidshielding means being spaced outwardly from the corresponding sides ofsaid light tube means, said light tube means, its light-shield means andsaid grid members being relatively positioned so that a line of sightthrough each longitudinal upper edge of said light-shielding means andthe lower longitudinal inner edge of the corresponding grid memberintersects the horizontal at an angle no less than that of the line ofsight between that shielding means edge and the upper limb of the lighttube means.

10. The ceiling of claim 9 wherein said unshielded portions of saidlight-reflective surface of said soundabsorbent means are exposed todirect upwardly traveling rays of light from said light tube means.

11. The ceiling of claim 9 wherein at least one of said grid membersadjacent said elongated tube means and in said line of sight alignmentwith said light-shielding means is hollow defining a longitudinalpassage, said grid member being provided with an air inlet means and anair outlet means.

12. The ceiling of claim 9 wherein at least one of said gird members ishollow, having an air register means 7 provided in a longitudinalsurface thereof, said one grid member being connected to an incommunication with a further hollow grid member in said ceiling, saidfurther grid member being connected to a supply of air, and discharginginto said grid member having said air register means.

13. The ceiling of claim 10 wherein said light shield means retractsdownwardly passing light to move at steeper angles to the horizontal.

14. A ceiling assembly adapted to be supported by overhead structure ina position below a horizontal lightreflective ceiling surface, saidassembly comprising a multiplicity of elongated grid members connectedtogether, a first group of said grid members being arranged inspaced-apart, parallel lines and a second group extending at rightangles thereto, a plurality of elongated light tube means each parallelwith and between a pair of parallel grid members of said first group,supported by grid members of said second group extending at right anglesthereto, the parallel grid members of said first group adjacent saidlight tube means each having a generally continuous surface parallelwith its light tube means and extending downwardly to a lowerlongitudinal horizontal edge below said light tube means, at least someof said grid members being hollow and adapted to convey air forVentilation, the outer surfaces of the grid members of said first groupdirected toward said light tube means being light-reflective, each lighttube means having a parallel elongated light shield means disposed underit, each said light shield means being narrower than the spacing betweenthe grid members of said first group lying adjacent thereto, and beingwider than the corresponding light tube means, the longitudinal upperedges of said shield means spaced outwardly from the corresponding sidesof said light tube means, each light tube means, its light shield meansand the corresponding parallel pair of grid members of said first groupbeing relatively positioned so that a line of sight through each lightshield means longitudinal upper edge and the lower longitudinal inneredge of the corresponding grid member intersects the horizontal at anangle no less than the line of sight between that shield means edge andthe upper limb of the corresponding light tube means.

15. The ceiling assembly of claim 14 wherein ends of hollow grid membersare connected together With the vol ume of one in communication with thevolume of another, one grid member connected to a source of ventilatingair and discharging into the other grid member in communicationtherewith.

16. The ceiling assembly of claim 14 wherein at least some of saidhollow grid members each is defined by relatively rigid thin wallsproviding a narrow undersurface, opposite, outwardly flaring side walls,and an upper longitudinal closing surface means cooperating to provide aceiling of generally even brightness while providing a large air passagecross section.

17. The ceiling assembly of claim 14 wherein each of said grid membersis provided with an upper supporting surface for supporting overlyingacoustical sheet means.

18. The ceiling assembly of claim 16 wherein at least some of said gridmembers have undersurfaces each defining an elongated engagement meansadapted to engage for positioning and support upper edge portions ofroom partitions.

19. An integrated illuminating, sound-absorbent ceiling comprising amultiplicity of elongated grid members adapted to be suspended inparallel, spaced-apart relation from overhead structure forming aplurality of spacedapart grid member pairs, each grid member providedwith an elongated upwardly directed support surface and an elongatedbottom edge, opaque acoustical sheet members having light-reflectivelower surfaces disposed over and supported in part by said upwardlydirected surfaces of said grid members, each sheet member extending inan overlying relation relative to the space between a pair of gridmembers, a plurality of elongated light source means, each light sourcemeans associated with a said pair of grid members, an elongated stripmember associated with each light source means, adapted to support saidlight source means therebelow, said strip member posilioning said lightsource means above said elongated bottom edges of said grid members,parallel therewith, and generally midway therebetween, said stripmembers providing upwardly directed support surfaces located in thevicinity of said light source means, engaging for support thecorresponding acoustical sheet members, each light source means and thecorresponding pair of grid members being relatively positioned so thatthe bottom edges of said grid members define cut-of} lines for lightpassing directly from said light source means at a predetermined smalldownward angle to the horizontal, to shield said light source means fromdirect view from the working area at angles to the horizontal smallerthan said predetermined angle, said acoustical sheet members havingmajor portions of their said lower surfaces extending from saidsupporting strip members to said supporting grid members exposeddirectly to illumination from said light source means, and exposedunimpededly to the working area rherebelow, whereby said opaqueacoustical sheet members serve as secondary sources of illumination tosaid working area, while said supporting grid members for saidacoustical sheer members cut off glare from said ceiling.

20. The ceiling of claim 19 wherein each light source means includes atleast one elongated light tube and an elongated shield means disposedbelow each light tube, each shield means constructed and arranged incooperation with the remaining elements of said ceiling to preventdirect view of said light tube at normal viewing angles from saidworking area, said shield means being sufiiciently narrow to maintainsaid acoustical sheet members unimpededly exposed to said working area.

2]. The ceiling of claim 19 having integral means de fining air passagesfor communication with the work space therebelow whereby said ceiling,as a single unit supported from overhead structure, serves theintegrated functions of illumination, air supply and acoustical damping.

22. The ceiling of claim 21 wherein at least some of said grid membersare hollow and define said air passages 23. The ceiling of claim 19wherein a pair of cross grid members is connected with a said pair ofgrid members, said cross-grid members spaced-apart and disposed at rightangles to said grid members, said cross grid members defining a pair ofelongated bottom edges positioned to cu't-ofi light passing directlyfrom said light source means at a predetermined small downward angle tothe horizontal, said cross-grid members providing upwardly directedsupport surfaces engaging and supporting corresponding portions of saidopaque acoustical sheet members.

References Cited in the file of this patent or the original patentUNITED STATES PATENTS 2,097,580 Tarbell Nov. 2, 1937 2,659,807 WakefieldNov. 17, 1953 2,659,808 Beckwith Nov. 17, 1953 2,781,110 Weller et alFeb. 12, 1957 2,803,741 Guth Aug. 20, 1957 2,833,199 Wakefield May 6,1958 2,888,113 Schwartz et al May 26, 1959 2,956,150 Schwartz et al.Oct. 11, 1960

